30 INTESTINAL ENTAMOEBAE OF MAN 



spheroidal and possess a thicker wall than those of E. 

 histolytica. When stained with iodin-eosin the cytoplasm 

 has a uniformly granular appearance; glycogen is seldom 

 present; and the nuclei, usually eight in number, are clearly 

 visible and possess a central granule often eccentric and 

 a layer of large granules of chromatin on the nuclear 

 membrane. 



c. Cysts of Endolimax nana (Plate III, Figs. 6, 7). Cysts 

 of E. nana range in diameter from 3 to 16 microns but are 

 usually no less than 5 and no greater than 12 microns in 

 diameter. Small and large races occur in this species as 

 in E. histolytica', the former vary from 4 to 8 microns and 

 are generally ellipsoidal, the larger races from 10 to 15 

 microns and are often ovoidal in shape. The nuclei furnish 

 the best diagnostic character. They are often obscured 

 by the many small vacuoles in the cytoplasm and in doubtful 

 cases cysts must be stained in iron haemotoxylin to bring 

 out their characteristics. No central chromatin granule is 

 present but all of the chromatin is usually aggregated in 

 one large mass and one or more smaller masses. 



Special Literature on Entamoebae 



CRAIG, C. F.: The Parasitic Amoebae of Man. Philadelphia, 1911. 

 DOBELL, C., AND JEPPS, M. W. : A Study of the Diverse Races of 



Entamoeba histolytica. Parasitology, Vol. 10, pp. 320-351, 



1918. 



DOBELL, C.: The Amoebae Living in Man. 155 pp. London, 1919. 

 KOFOID, C. A., KORNHATJSER, S. I., AND SWEZY, O. : Criterions for 



Distinguishing the Endamoeba of Amebiasis from Other 



Organisms. Archives of Internal Medicine, Vol. 24, pp. 



35-50, 1919. 

 WENYON, C. M., AND O'CONNOR, F. W.: Human Intestinal Protozoa 



in the Near East. 218 pp. London, 1917. 



